1. Field of the Invention
This invention relates to silicone sealants which cure upon exposure to moisture.
2. Background Information
Silicone sealant compositions which cure upon exposure to moisture have been developed which make use of various cure mechanisms. One of these is a combination of hydroxyl endblocked polydiorganosiloxane acetamidosilane chain extender and aminoxysilicon crosslinking system. Such a system is used in U.S. Pat. No. 4,810,748, issued Mar. 7, 1989.
U.S. Pat. No. 3,817,909. issued June 18, 1974, teaches a low modulus room temperature vulcanizable silicone elastomer obtained by mixing a hydroxyl endblocked polydiorganosiloxane, filler, acetamido containing chain extender, and crosslinker which is an aminoxysilicon compound having 3 to 10 aminoxy groups per molecule.
Another cure mechanism makes use of silicon-bonded oxime radicals. U.S. Pat. No. 3,189,576, issued June 15, 1965, relates to organosilicon intermediates containing as functional groups silicon-bonded oxime radicals. Compounds containing an average of more than 2 oxime radicals per molecule are taught as useful as an intermediate in one-component room temperature curing coating and caulking compositions.
U.S. Pat. No. 4,503,210, issued Mar. 5, 1985, teaches oxime containing compositions which crosslink in the presence of moisture to form elastomers at room temperature. Compositions comprising a diorganopolysiloxane having terminal condensable groups and a silicon compound having at least three oxime groups per molecule bonded to silicon via oxygen are taught. A portion of the silicon compound is replaced by a mixture containing a silane having four oxime groups bonded to silicon via oxygen and a silane having a hydrocarbon radical bonded to a silicon atom via a SiC-bonding and having three oxime groups bonded to the silicon atom via oxygen.